An arc suppression circuit and method

Abstract

The application discloses an arc extinguishing circuit and method, and the arc extinguishing circuit comprises a state reading circuit, a sampling circuit and a control circuit. The state reading circuit reads the action state information of a protection switch device. The sampling circuit collects electrical state information. The control circuit controls the input of an absorption circuit according to the action state information and the electrical state information. When the protection switch device is in the action state and there is a load current signal, the absorption circuit is inputted to perform arc extinguishing operation after the load is judged as a direct current load by identifying the load signal. The application can judge whether there is a possibility of arc generation in the protection switch device, and then input the absorption circuit to eliminate the arc between the relay contacts, solve the problem that the absorption circuit is affected by the bypass to cause the failure of the on-line detection of the breaking and closing coil function of the device, avoid the damage of the surge current to the contacts and the risk that the relay is failed due to the arc erosion of the relay contacts, and prolong the service life of the relay.

Description

Technical Field

[0001] This invention relates to the field of relay protection technology, specifically to an arc suppression method and circuit. Background Technology

[0002] Microprocessor-based relay protection devices (hereinafter referred to as devices) are widely used in power systems. They accurately determine changes in the operating status of power equipment by monitoring signals such as current and voltage. When the operating data is abnormal or the monitoring system issues an operation signal, the device issues a trip (close) command to control the circuit breaker to perform a trip (close) operation.

[0003] After the device issues a trip (close) command, the internal relay contacts connect the circuit breaker trip (close) coil, thereby driving the circuit breaker operating mechanism to complete the trip (close) operation. After the operation is completed, the circuit breaker auxiliary contacts disconnect the connection between the trip (close) coil and the relay contacts, and then the relay returns to its original position without load.

[0004] Because the relay contacts are close together, the trip (closing) coil can be connected and disconnected when powered by AC. When powered by DC, the circuit breaker trip (closing) coil can only be connected. It cannot be returned under load when the circuit breaker trip (closing) coil is connected, otherwise an electric arc will easily be generated between the contacts, burning the relay contacts and contact plates, thus causing the relay to fail.

[0005] The traditional method to eliminate electric arc is to connect an RC snubber circuit in parallel across the relay contacts. However, this method charges the capacitor when the relay contacts are open, and the surge current generated by the capacitor discharge when the contacts are closed can also damage the contacts. At the same time, due to the bypass effect of the snubber circuit, the function of the device to detect the trip (close) coil online may also fail. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the problem that the surge current generated by capacitor discharge in the traditional arc suppression circuit in the prior art will damage the relay contacts and cause the relay to fail, thereby providing an arc suppression circuit and method.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] In a first aspect, embodiments of the present invention provide an arc suppression circuit applied to a protective switching device. The first terminal of the protective switching device is connected to a positive power line, and the second terminal is connected to a negative power line. The arc suppression circuit includes: a status reading circuit, a sampling circuit, an absorption circuit, and a control circuit. The first terminal of the status reading circuit is connected to the third terminal of the protective switching device, the second terminal of the status reading circuit is connected to the fourth terminal of the protective switching device, and the third terminal of the status reading circuit is connected to the first terminal of the control circuit. The status reading circuit reads the operating status information of the protective switching device according to the status reading signal issued by the control circuit. The first terminal of the sampling circuit is connected to the fifth terminal of the protective switching device, and the second terminal of the sampling circuit... The sampling circuit is connected to the sixth terminal of the protection switch, and the third terminal of the sampling circuit is connected to the second terminal of the control circuit. The sampling circuit reads the electrical status information of the protection switch based on the sampling signal sent by the control circuit. The first terminal of the absorption circuit is connected to the sixth terminal of the protection switch, the second terminal of the absorption circuit is connected to the second terminal of the protection switch, and the third terminal of the absorption circuit is connected to the third terminal of the control circuit. The control circuit is used to determine whether the protection switch is in an operating state and whether the load of the protection switch is a DC load based on the operating status information and electrical status information of the protection switch. When the protection switch is in an operating state and the load of the protection switch is a DC load, the absorption circuit is activated.

[0009] In one embodiment, the status reading circuit includes: a first isolation circuit and a first diode, wherein a first terminal of the first isolation circuit is connected to the anode of the first diode, a second terminal of the first isolation circuit is connected to the first terminal of the control circuit; the cathode of the first diode is connected to the third terminal of the protection switch device, and the anode of the first diode is connected to the fourth terminal of the protection switch device.

[0010] In one embodiment, the sampling circuit includes: a nonlinear current sampling circuit, a second isolation circuit, and a first filter circuit. The first and second terminals of the nonlinear current sampling circuit are connected to the fifth and sixth terminals of the protection switch device, respectively. The third and fourth terminals of the nonlinear current sampling circuit are connected to the first and second terminals of the second isolation circuit, respectively. The third terminal of the second isolation circuit is connected to an external power supply, and the fourth terminal of the second isolation circuit is connected to the first terminal of the first filter circuit. The second terminal of the first filter circuit is connected to the second terminal of the control circuit.

[0011] In one embodiment, the absorption circuit includes: a third isolation circuit, a second diode, a control switch circuit, and an RC absorption circuit, wherein a first terminal of the third isolation circuit is connected to the anode of the second diode, and a second terminal of the third isolation circuit is connected to a third terminal of the control circuit; the cathode of the second diode is connected to a first terminal of the control switch circuit, and the anode of the second diode is connected to a second terminal of the control switch circuit; a third terminal of the control switch circuit is connected to a sixth terminal of the protection switch device, a fourth terminal of the control switch circuit is connected to a first terminal of the RC absorption circuit, and a second terminal of the RC absorption circuit is connected to a second terminal of the protection switch device.

[0012] In one embodiment, the arc suppression circuit further includes: a position reading circuit; a first terminal of the position reading circuit is connected to a first terminal of the protective switch device, a second terminal of the position reading circuit is connected to a sixth terminal of the protective switch device, and a third terminal of the position reading circuit is connected to a fourth terminal of the control circuit. The position reading circuit is used to read the position information of the protective switch device according to the position reading signal sent by the control circuit, and to determine whether the protective switch device is operating normally according to the position information.

[0013] In one embodiment, the position reading circuit includes: a fourth isolation circuit and a second filter circuit, wherein the first terminal of the fourth isolation circuit is connected to the first terminal of the protection switch device, the second terminal of the fourth isolation circuit is connected to the sixth terminal of the protection switch device, the third terminal of the fourth isolation circuit is connected to an external power supply, and the fourth terminal of the fourth isolation circuit is connected to the first terminal of the second filter circuit; the second terminal of the second filter circuit is connected to the fourth terminal of the control circuit.

[0014] In one embodiment, the arc suppression circuit further includes a storage circuit; the storage circuit is connected to the ninth and tenth terminals of the control circuit; when the control circuit determines that the protection switch device has not operated normally, the control circuit writes the fault information of the protection switch device into the storage circuit.

[0015] Secondly, embodiments of the present invention provide an arc suppression method, which applies an arc suppression circuit as provided in another embodiment of the present invention. The arc suppression method includes: reading the operation status information of a protective switch device and determining whether the protective switch device is in an operational state; when the protective switch device is in an operational state, reading the electrical status information of the protective switch device; determining whether the load of the protective switch device is a DC load based on the electrical status information of the protective switch device; and controlling the absorption circuit to be activated when the protective switch device is in an operational state and the load of the protective switch device is a DC load.

[0016] In one embodiment, the process of determining whether the load of the protective switch device is a DC load based on the electrical status information includes: when the electrical status information indicates that there is a load current signal, determining whether the load current signal is a continuous signal; when the load current signal is a continuous signal, determining that the load of the protective switch device is a DC load.

[0017] In one embodiment, the process of determining whether the load of the protective switch device is a DC load based on the electrical status information further includes: when the electrical status information is a no-load current signal or the load current signal is a pulse signal, reading the position information of the protective switch device; determining whether the protective switch device is operating normally based on the position information; and when the protective switch device is operating normally, returning to the step of "reading the operation status information of the protective switch device and determining whether the protective switch device is in an operating state".

[0018] In one embodiment, the process of controlling the absorption circuit to be engaged includes: controlling the absorption circuit to be engaged continuously for a preset time, and then controlling the absorption circuit to be disengaged.

[0019] In one embodiment, the arc suppression method further includes: when the protection switch is not in an operating state, returning to the step of "reading the operating state information of the protection switch and determining whether the protection switch is in an operating state".

[0020] The technical solution of this invention has the following advantages:

[0021] 1. The arc suppression circuit provided by the present invention includes a status reading circuit that reads the operating status information of the protective switch device, a sampling circuit that collects electrical status information, and a control circuit that controls the activation and deactivation of the absorption circuit based on the operating status information and the electrical status information, thereby eliminating the electric arc between the relay contacts, avoiding the risk of relay failure due to arc burning of the relay contacts, and extending the service life of the relay.

[0022] 2. The arc suppression method provided by the present invention, when the protective switch device is detected to be in an active state and there is a load current signal, identifies the load signal and determines that the load state is a DC load, and then controls the activation and deactivation of the absorption circuit, thereby eliminating the arc between the relay contacts. This solves the problem of the absorption circuit failing to detect the opening and closing coils of the circuit breaker online due to the bypass effect, avoids damage to the contacts caused by surge current, and extends the service life of the relay. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a composition diagram of a specific example of the arc suppression circuit provided in an embodiment of the present invention;

[0025] Figure 2 This is a circuit structure diagram of the status reading circuit provided in an embodiment of the present invention;

[0026] Figure 3 This is a circuit structure diagram of the sampling circuit provided in an embodiment of the present invention;

[0027] Figure 4 This is a circuit structure diagram of the absorption circuit provided in an embodiment of the present invention;

[0028] Figure 5 This is a composition diagram of another specific example of the arc suppression circuit provided in an embodiment of the present invention;

[0029] Figure 6 This is a circuit structure diagram of the position reading circuit provided in an embodiment of the present invention;

[0030] Figure 7 The circuit structure diagram of the control circuit and storage circuit provided in the embodiments of the present invention is shown below;

[0031] Figure 8 A flowchart illustrating a specific example of the arc extinguishing method provided in this embodiment of the invention;

[0032] Figure 9 A flowchart illustrating another specific example of the arc-extinguishing method provided in this embodiment of the invention;

[0033] Figure 10 This is a flowchart illustrating the arc suppression method provided in this embodiment of the invention. Detailed Implementation

[0034] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] Example 1

[0039] This invention provides an arc suppression circuit, which can be applied to any electrical equipment that may generate electric arcs, such as transmission lines, high-voltage electrical appliances, and other equipment. Figure 1 As shown, the first terminal of the protection switch is connected to the positive power line (+KM), and the second terminal of the protection switch is connected to the negative power line (-KM). The arc suppression circuit includes: a status reading circuit 1, a sampling circuit 2, an absorption circuit 3, and a control circuit 5. Figure 1 The protective switchgear consists of a drive relay and a circuit breaker coil, but this is only an example and is not a limitation.

[0040] like Figure 1 As shown, the first end of the status reading circuit 1 is connected to the third end of the protection switch device, the second end of the status reading circuit 1 is connected to the fourth end of the protection switch device, and the third end of the status reading circuit 1 is connected to the first end of the control circuit 5. The status reading circuit 1 reads the operation status information of the protection switch device according to the status reading signal sent by the control circuit 5.

[0041] For example, taking a protective switching device that includes a drive relay and a circuit breaker coil as an example, the status reading circuit 1 is actually connected to the drive relay to read the status of the drive relay, which includes an active status and a non-active status.

[0042] like Figure 1 As shown, the first end of the sampling circuit 2 is connected to the fifth end of the protection switch device, the second end of the sampling circuit 2 is connected to the sixth end of the protection switch device, and the third end of the sampling circuit 2 is connected to the second end of the control circuit. The sampling circuit 2 reads the electrical status information of the protection switch device according to the sampling signal sent by the control circuit.

[0043] For example, taking a protective switching device that includes a drive relay and a circuit breaker coil as an example, the sampling circuit 2 is connected in series between the drive relay and the circuit breaker coil to obtain the electrical status information of the line in real time.

[0044] like Figure 1 As shown, the first end of the absorption circuit 3 is connected to the sixth end of the protection switch device, the second end of the absorption circuit 3 is connected to the second end of the protection switch device, and the third end of the absorption circuit 3 is connected to the third end of the control circuit.

[0045] For example, taking a protective switching device that includes a drive relay and a circuit breaker coil as an example, the absorption circuit 3 is actually connected in parallel with the circuit breaker coil to absorb the energy stored in the circuit breaker coil.

[0046] like Figure 1 As shown, the control circuit 5 is used to determine whether the protection switch is in an operating state and whether the load of the protection switch is a DC load based on the operation status information and electrical status information of the protection switch. When the protection switch is in an operating state and the load of the protection switch is a DC load, the control absorption circuit 3 is activated.

[0047] Specifically, the absorption circuit 3 in this embodiment of the invention is not directly connected in parallel with the relay contacts or the circuit breaker coil. Instead, it employs a controllable switching absorption circuit 3. The protection of the switching device in an operational state and the presence of a DC load serve as the basis for determining whether an electric arc may be generated inside the electrical device. When an arc is likely to occur, the absorption circuit is activated to eliminate the arc between the contacts. This avoids damage to the contacts caused by surge currents generated when the relay contacts are open (charging the capacitor) or closed (discharging the capacitor), thus preventing the trip (close) coil from malfunctioning.

[0048] Specifically, when the drive relay in the protection switch device does not operate, there is no load current signal in the device, or the load current is an AC load, there is no possibility of arc generation between the relay contacts, so there is no need to engage the absorption circuit for arc suppression.

[0049] It should be noted that, since the relay has a closing coil and a closing coil, and each of the two coils is configured with a driving relay, the number of the status reading circuit, sampling circuit, absorption circuit and position reading circuit in this embodiment of the invention needs to be set as needed.

[0050] In one specific embodiment, such as Figure 2 As shown, the status reading circuit 1 includes: a first isolation circuit 11 and a first diode D1, wherein the first end of the first isolation circuit 11 is connected to the anode of the first diode D1, the second end (Kout1 end) of the first isolation circuit 11 is connected to the first end (Kout1 end) of the control circuit; the cathode of the first diode D1 is connected to the third end of the protection switch device (drive relay RELAY1), and the anode of the first diode D1 is connected to the fourth end of the protection switch device (drive relay RELAY1).

[0051] Optionally, such as Figure 2 As shown, the first isolation circuit 11 includes a current-limiting resistor R1 and a first isolation coupler U1.

[0052] like Figure 2 As shown, the first end (Kout1 end) of the current limiting resistor R1 is connected to the first end (Kout1 end) of the control circuit 5, the second end of the current limiting resistor R1 is connected to the first end of the first isolation coupler U1, and the second end of the first isolation coupler U1 is connected to the anode of the first diode D1.

[0053] Specifically, such as Figure 2 As shown, when the device issues a closing command, the first and second terminals of the status reading circuit 1 identify the operating status of the protection switch device (drive relay RELAY1). The operating status signal is converted into a level signal through the first isolation coupler U1 and the current limiting resistor R1. The first terminal (Kout1 terminal) of the control circuit 5 reads the level signal through the interface Kout1 and determines whether the drive relay RELAY1 is in the operating state based on the level signal. For example, when the interface Kout1 is read as high, it is determined that the drive relay RELAY1 is in the operating state. When the drive relay RELAY1 returns, the first diode D1 plays the role of freewheeling, releasing the energy stored in the circuit breaker coil.

[0054] In one specific embodiment, such as Figure 3As shown, the sampling circuit 2 includes: a nonlinear current sampling circuit 21, a second isolation circuit 22, and a first filter circuit 23. The first terminal (terminal 103) and the second terminal (terminal 107) of the nonlinear current sampling circuit 21 are connected to the fifth terminal and the sixth terminal of the protection switch device, respectively, meaning that the nonlinear current sampling circuit 21 is connected in series with the internal wiring of the protection switch device. The third terminal and the fourth terminal of the nonlinear current sampling circuit 21 are connected to the first terminal and the second terminal of the second isolation circuit 22, respectively. The third terminal of the second isolation circuit 22 is connected to an external power supply, and the fourth terminal of the second isolation circuit 22 is connected to the first terminal of the first filter circuit 23. The second terminal (Kin1 terminal) of the first filter circuit 23 is connected to the second terminal (Kin1 terminal) of the control circuit 5.

[0055] Optionally, such as Figure 3 As shown, the nonlinear current sampling circuit 21 includes: resistor R2 and four diodes connected end to end; the second isolation circuit 22 includes: resistor R3 and second isolation coupler U2; the first filter circuit 23 includes: resistor R4 and capacitor C1.

[0056] like Figure 3 As shown, four diodes are connected end to end. Two adjacent diodes are connected in parallel with resistor R2. The first end (terminal 103) of the parallel connection is connected to the first end of resistor R3. The second end (terminal 107) of the parallel connection is connected to the third end of the second isolation coupler U2. The second end of resistor R3 is connected to the first end of the second isolation coupler U2. The sixth end of the second isolation coupler U2 is connected to the external power supply. The fourth end of the second isolation coupler U2 is connected to the first end of resistor R4. The second end of resistor R4 and the first end of capacitor C1 are both connected to the second end (Kin1) of control circuit 5. The second end of capacitor C1 is grounded.

[0057] Specifically, when the second terminal (Kin1 terminal) of the control circuit 5 sends a sampling signal, the second isolation circuit is turned on, the nonlinear current sampling circuit 21 collects the load current signal in the protection switch device and performs rectification operation on the load current. The rectified load current signal is obtained after passing through the second isolation circuit 22 and the first filter circuit 23 to obtain a stable load current signal. The second terminal (Kin1 terminal) of the control circuit 5 reads the level signal through the Kin1 interface and determines whether the drive relay RELAY1 is in the operating state based on the level signal. For example, when the interface Kin1 is read as high, it is determined that there is load current, and when the load current is continuous, it is determined that the load current in the protection switch device is a DC load.

[0058] It should be noted that the first filter circuit 23 in this embodiment of the invention is not limited to an RC filter circuit composed of capacitor C1 and resistor R4, but can also be other filter circuits with the same function, which are not limited here.

[0059] In one specific embodiment, such as Figure 4 As shown, the absorption circuit 3 includes: a third isolation circuit 31, a second diode D2, a control switch circuit 32, and an RC absorption circuit 33. The first terminal of the third isolation circuit 31 is connected to the anode of the second diode D2, and the second terminal (Kout3 terminal) of the third isolation circuit 31 is connected to the third terminal (Kout3 terminal) of the control circuit 5. The cathode of the second diode D2 is connected to the first terminal of the control switch circuit 32, and the anode of the second diode D2 is connected to the second terminal of the control switch circuit 32. The third terminal (107 terminal) of the control switch circuit 32 is connected to the sixth terminal of the protective switch device, and the fourth terminal of the control switch circuit 32 is connected to the first terminal of the RC absorption circuit 33. The second terminal (102 terminal) of the RC absorption circuit 33 is connected to the second terminal of the protective switch device. That is, when the protective switch device includes a drive relay and a circuit breaker coil... Figure 4 In the circuit breaker, terminals 107 and 102 are connected in parallel with the circuit breaker coil.

[0060] Optionally, such as Figure 4 As shown, the third isolation circuit 31 includes: resistor R5 and third isolation coupler U3; the RC snubber circuit includes: resistor R6 and capacitor C2.

[0061] like Figure 4 As shown, the first end of resistor R5 is connected to the third end (Kout3) of control circuit 5, the second end of resistor R5 is connected to the first end of third isolation coupler U3, the second end of third isolation coupler U3 and the anode of diode D2 are both connected to the second end of control switch circuit 32, the first end of capacitor C2 and the first end of resistor R6 are both connected to the fourth end of control switch circuit 32, and the second end of capacitor C2 and the second end (102 end) of resistor R6 are both connected to the second end of protection switch device.

[0062] Specifically, capacitor C2 in the RC absorption circuit is used to absorb the energy stored in the coil of the protective switching device, and resistor R6 is used to release the residual electrical energy inside capacitor C2, thereby eliminating the electric arc between the contacts of the driving relay RELAY1.

[0063] Specifically, when arc suppression is required, control circuit 5 sends an activation signal to control the activation of absorption circuit 3, for example: Figure 4 As shown, when the control circuit 5 sets the third terminal (Kout3 terminal) to a high level, the current signal passes through the third isolation circuit 31 to close the contacts of the control switch circuit 32, thereby activating the RC absorption circuit 33; after a preset delay of 0.2 seconds, the control circuit 5 will... Figure 2When interface Kout1 is set to low level, relay RELAY1 is driven to return; after a preset delay of 0.2 seconds, control circuit 5 sets interface Kout3 to low level, and the current signal passes through the third isolation circuit 31 to open the contacts of control switch circuit 32. After the second diode D2 releases the energy stored in the circuit breaker coil, RC absorption circuit 33 is switched off.

[0064] It should be noted that the preset time for the absorption circuit to continuously engage and disengage in the embodiments of the present invention is not limited to 0.2 seconds, and is not limited here.

[0065] In one specific embodiment, such as Figure 5 As shown, the arc suppression circuit also includes a position reading circuit 4. The first end of the position reading circuit 4 is connected to the first end (+KM) of the protection switch device, the second end of the position reading circuit 4 is connected to the sixth end of the protection switch device, and the third end of the position reading circuit 4 is connected to the fourth end (Kin3 end) of the control circuit. The position reading circuit 4 is used to read the position information of the protection switch device according to the position reading signal sent by the control circuit, and to determine whether the protection switch device is operating normally according to the position information.

[0066] Specifically, such as Figure 6 As shown, the position reading circuit 4 in this embodiment of the invention includes a fourth isolation circuit 41 and a second filter circuit 42. The first end (101 end) and the second end (107 end) of the fourth isolation circuit 41 are respectively connected to the first end and the sixth end of the protection switch device. The third end of the fourth isolation circuit 41 is connected to an external power supply. The fourth end of the fourth isolation circuit 41 is connected to the first end of the second filter circuit 42. The second end (Kin3 end) of the second filter circuit 42 is connected to the fourth end (Kin3 end) of the control circuit 5.

[0067] Optionally, such as Figure 6 As shown, the fourth isolation circuit 41 includes: resistor R7, resistor R8 and fourth isolation coupler U4; the second filter circuit 42 includes: resistor R9 and capacitor C3.

[0068] Specifically, the first end (101 end) of resistor R7 is connected to the first end of the protection switch device, the second end of resistor R7 and the first end of resistor R8 are both connected to the first end of the fourth isolation coupler U4, the second end of resistor R8 and the third end (107 end) of the fourth isolation coupler U4 are both connected to the sixth end of the protection switch device, the sixth end of the fourth isolation coupler U4 is connected to the external power supply, the fourth end of the fourth isolation coupler U4 is connected to the first end of resistor R9, the second end of resistor R9 and the first end of capacitor C3 are both connected to the fourth end (Kin3 end) of control circuit 5, and the second end of capacitor C3 is grounded.

[0069] Specifically, the position reading circuit 4 determines the position information based on the current signal in the protection switch device, and determines whether the protection switch device is operating normally based on the position information. When the drive relay RELAY1 returns, the contacts of the drive relay RELAY1 change from the closed state to the open state. At this time, no current flows through the circuit where the drive relay RELAY1 is located, and the interface Kin3 of the control circuit 5 is at a low level, thus determining that the circuit breaker is operating normally. If the drive relay does not operate normally, that is, the contacts of the drive relay RELAY1 are still in the closed state, then current flows through the circuit where the drive relay RELAY1 is located. After the current signal is converted into a stable load current signal through the fourth isolation circuit 41 and the second filter circuit 42, the interface Kin3 of the control circuit 5 is set to a high level, thus determining that the circuit breaker has not operated normally.

[0070] Specifically, the first isolation circuit, the second isolation circuit, the third isolation circuit, and the fourth isolation circuit in the embodiments of the present invention can all be made of optocouplers, but this is only an example and is not intended to limit the scope of the invention.

[0071] It should be noted that the second filter circuit 42 in this embodiment of the invention is not limited to the RC filter circuit composed of capacitor C3 and resistor R9, but can also be other filter circuits with the same function, which are not limited here.

[0072] In one specific embodiment, the arc suppression circuit further includes a storage circuit, the specific structure of which is as follows: Figure 7 As shown, the control circuit is mainly based on the MCU chip, and the storage circuit is connected to the ninth and tenth terminals of the control circuit through resistors R10 and R11 to improve the stability of the communication line. When the control circuit determines that the protection switch device has not operated normally, the control circuit writes the fault information of the protection switch device into the storage circuit.

[0073] The arc suppression circuit provided in this embodiment of the invention can be applied to both closing and tripping operations simultaneously. The arc suppression circuit described in the above embodiment is only the arc suppression circuit used for relay action and return during the device's closing operation. Wherein, as Figure 7 As shown, the status reading circuit 1, sampling circuit 2, absorption circuit 3, and position reading circuit 4 are respectively connected to interfaces Kout1, Kin1, Kout3, and Kin3 of the control circuit 5. When performing a tripping operation, the arc suppression circuit used is the same as the arc suppression circuit used during the closing operation; only the connections between each circuit and the control circuit 5 need to be adjusted. For example, Figure 7 As shown, the status reading circuit 1, sampling circuit 2, absorption circuit 3 and position reading circuit 4 are respectively connected to the interfaces Kout2, Kin2, Kout4 and Kin4 of the control circuit 5.

[0074] Example 2

[0075] This invention provides an arc suppression method, which is applied to the arc suppression circuit of Embodiment 1, such as... Figure 8 As shown, the arc extinguishing method includes the following steps:

[0076] Step S1: Read the operating status information of the protection switch and determine whether the protection switch is in an operating state. If it is in an operating state, proceed to step S2.

[0077] Step S2: When the protective switch is in the activated state, read the electrical status information of the protective switch. The electrical status information of the protective switch can be the load current signal within the protective switch.

[0078] Step S3: Based on the electrical status information of the protection switch, determine whether the load of the protection switch is a DC load. If it is a DC load, proceed to step S4.

[0079] Step S4: When the protection switch is in the activated state and the load of the protection switch is a DC load, the control absorption circuit is activated.

[0080] Traditional methods for extinguishing electric arcs involve directly connecting an absorption circuit in parallel across the relay contacts. However, this approach charges the capacitor when the relay contacts open, and the surge current generated by the capacitor's discharge when the relay closes can damage the contacts. Furthermore, the bypass effect of the absorption circuit can cause the device's online detection of the trip (close) coil to malfunction. The arc-extinguishing method provided in this invention selectively engages the absorption circuit by reading the operating status information and load current information of the protective switch, thus extinguishing any potential arcs between the contacts and preventing the contacts from being burned by the arc when the relay returns. Since any electrical appliance with contacts can generate arcs when the contacts are connected and disconnected, the arc-extinguishing method of this invention can be applied to any electrical equipment that may generate arcs, such as transmission lines, high-voltage electrical appliances, and other equipment, without limitation.

[0081] In one specific embodiment, such as Figure 9 As shown, step S3 includes the following steps:

[0082] Step S31: When the electrical status information indicates a load current signal, determine whether the load current signal is a continuous signal.

[0083] Step S32: When the load current signal is a continuous signal, the load of the protection switch device is determined to be a DC load.

[0084] In one specific embodiment, the process of determining whether the load of the protection switch device is a DC load based on the electrical status information of the protection switch device further includes the following cases:

[0085] (1) When there is no load current signal, read the position information of the protection switch device. When it is detected that there is no load current signal in the protection switch device, it is determined that the protection switch device may have returned normally. Then, read the position of the protection switch device. If the protection switch device has indeed returned normally, return to step S1; otherwise, write the fault information into the storage circuit.

[0086] (2) When the load current signal is a pulse signal, read the position information of the protection switch device. When the load current signal is a pulse signal, it is determined that the load current is an AC load and there is no possibility of arcing in the contacts of the protection switch device. At this time, the protection switch device is allowed to return. After returning, the position of the protection switch device is read again. If the protection switch device does return normally, return to step S1; otherwise, write the fault information into the storage circuit.

[0087] In one specific embodiment, such as Figure 8 As shown, step S4, which controls the absorption circuit to be engaged, includes: controlling the absorption circuit to be engaged continuously for a preset time, and then controlling the absorption circuit to be disengaged.

[0088] Specifically, after the absorption circuit is engaged, it absorbs the energy stored in the protection switch device for 0.2 seconds, thereby eliminating the possibility of arc generation and controlling the protection switch device to return; after another 0.2 seconds, it exits the absorption circuit, ending the arc suppression operation.

[0089] In one specific embodiment, the arc extinguishing method further includes: when the protection switch device is not in an activated state, returning to step S1.

[0090] The arc-suppression method provided in this embodiment of the invention can be applied to arc-suppression operations in both closing and tripping situations. The arc-suppression method described in the above embodiments is only the arc-suppression method used for relay action and return during device closing operation. When performing a tripping operation, the arc-suppression method used is the same as the method used during closing operation. For example, as shown... Figure 10 As shown, the arc extinguishing method during the closing operation is as follows:

[0091] (1) When the drive relay RELAY1 does not operate, wait for the drive relay RELAY1 to operate; when the drive relay RELAY1 operates, identify whether there is load current in the protection switch device.

[0092] (2) If there is no load current, drive relay RELAY1 back and proceed to step (4) to determine whether the circuit breaker is operating normally; if there is load current, determine whether the load current is a DC load.

[0093] (3) If it is an AC load, drive relay RELAY1 back and proceed to step (4) to determine whether the circuit breaker operates normally; if it is a DC load, engage the RC snubber circuit, drive relay RELAY1 back after a delay of 0.2 seconds, and then exit the RC snubber circuit after another delay of 0.2 seconds, proceed to step (4) to determine whether the circuit breaker operates normally.

[0094] (4) If the circuit breaker operates normally, return to step (1); if the circuit breaker does not operate normally, write the fault information into the storage circuit.

[0095] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An arc suppression circuit, characterized in that, This is applied to a protective switching device, wherein the first end of the protective switching device is connected to the positive power line, and the second end of the protective switching device is connected to the negative power line. The arc suppression circuit includes: a status reading circuit, a sampling circuit, an absorption circuit, and a control circuit. A status reading circuit has its first terminal connected to the third terminal of the protective switch device, its second terminal connected to the fourth terminal of the protective switch device, and its third terminal connected to the first terminal of the control circuit. It is used to read the operation status information of the protective switch device based on the status reading signal issued by the control circuit. The sampling circuit has its first terminal connected to the fifth terminal of the protective switch device, its second terminal connected to the sixth terminal of the protective switch device, and its third terminal connected to the second terminal of the control circuit. It is used to read the electrical status information of the protective switch device based on the sampling signal issued by the control circuit. An absorption circuit, the first end of which is connected to the sixth end of the protective switch device, the second end of which is connected to the second end of the protective switch device, and the third end of which is connected to the third end of the control circuit; A control circuit is used to determine whether the protection switch is in an operating state and whether the load of the protection switch is a DC load based on the operating state information and the electrical state information of the protection switch; when the protection switch is in an operating state and the load of the protection switch is a DC load, the circuit is controlled to activate the absorption circuit.

2. The arc suppression circuit according to claim 1, characterized in that, The status reading circuit includes: a first isolation circuit and a first diode, wherein... A first isolation circuit, wherein a first terminal is connected to the anode of the first diode, and a second terminal is connected to the first terminal of the control circuit; The first diode has its cathode connected to the third terminal of the protection switch device and its anode connected to the fourth terminal of the protection switch device.

3. The arc suppression circuit according to claim 1, characterized in that, The sampling circuit includes: a nonlinear current sampling circuit, a second isolation circuit, and a first filter circuit, wherein... A nonlinear current sampling circuit, wherein its first and second ends are connected to the fifth and sixth ends of the protection switch device, and its third and fourth ends are connected to the first and second ends of the second isolation circuit. The second isolation circuit has its third terminal connected to an external power supply and its fourth terminal connected to the first terminal of the first filter circuit. The second terminal of the first filter circuit is connected to the second terminal of the control circuit.

4. The arc suppression circuit according to claim 1, characterized in that, The absorption circuit includes: a third isolation circuit, a second diode, a control switch circuit, and an RC absorption circuit, wherein... The third isolation circuit has its first terminal connected to the anode of the second diode and its second terminal connected to the third terminal of the control circuit. The second diode has its cathode connected to the first terminal of the control switch circuit and its anode connected to the second terminal of the control switch circuit. The control switch circuit has its third terminal connected to the sixth terminal of the protection switch device, and its fourth terminal connected to the first terminal of the RC absorption circuit. An RC snubber circuit, the second terminal of which is connected to the second terminal of the protective switch device.

5. The arc suppression circuit according to claim 1, characterized in that, Also includes: A position reading circuit, with its first terminal connected to the first terminal of the protective switch device, its second terminal connected to the sixth terminal of the protective switch device, and its third terminal connected to the fourth terminal of the control circuit, is used to read the position information of the protective switch device based on the position reading signal issued by the control circuit. The control circuit determines whether the protective switch device is operating normally based on the position information.

6. The arc suppression circuit according to claim 5, characterized in that, The position reading circuit includes: a fourth isolation circuit and a second filtering circuit, wherein... The fourth isolation circuit has its first end connected to the first end of the protection switch device, its second end connected to the sixth end of the protection switch device, its third end connected to the external power supply, and its fourth end connected to the first end of the second filter circuit. The second filter circuit has its second terminal connected to the fourth terminal of the control circuit.

7. The arc suppression circuit according to claim 5, characterized in that, Also includes: A storage circuit, which is connected to the ninth and tenth terminals of the control circuit; When the control circuit determines that the protection switch device has not operated normally, the control circuit writes the fault information of the protection switch device into the storage circuit.

8. An arc-extinguishing method, characterized in that, The method, applied to the arc suppression circuit according to any one of claims 1-7, comprises: Read the operation status information of the protection switch device and determine whether the protection switch device is in an operational state; When the protective switch is in the activated state, read the electrical status information of the protective switch. Based on the electrical status information, determine whether the load of the protection switch device is a DC load; When the protection switch is in the activated state and the load of the protection switch is a DC load, the absorption circuit is activated.

9. The arc extinguishing method according to claim 8, characterized in that, The process of determining whether the load of the protection switch device is a DC load based on the electrical state information includes: When the electrical status information indicates a load current signal, determine whether the load current signal is a continuous signal; When the load current signal is a continuous signal, the load of the protection switch device is determined to be a DC load.

10. The arc extinguishing method according to claim 9, characterized in that, The process of determining whether the load of the protection switch device is a DC load based on the electrical state information further includes: When the electrical status information is a no-load current signal, or the load current signal is a pulse signal, read the position information of the protection switch device; Based on the location information, determine whether the protective switch device is operating normally; When the protection switch device operates normally, return to the step of "reading the operation status information of the protection switch device and determining whether the protection switch device is in an operating state".

11. The arc extinguishing method according to claim 8, characterized in that, The process of controlling the activation of the absorption circuit includes: After the absorption circuit has been continuously engaged for a preset time, the absorption circuit is controlled to deactivate.

12. The arc extinguishing method according to claim 8, characterized in that, Also includes: When the protection switch is not in an activated state, the fault information of the protection switch is written into the storage circuit.

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